faking GADTs

copy/entries/fake-gadts.md

@@ -0,0 +1,22 @@
+---
+title: Faking GADTs in Languages That Shouldn't Have Them
+categories: Haskell
+tags: functional programming, haskell, purescript, dhall, java
+create-time: 2024/11/12 13:59:35
+identifier: fake-gadts
+slug: faking-gadts-in-languages-that-shouldnt-have-them
+---
+
+Haskell is the world's best programming language, but let's face the harsh
+reality that a lot of times in life you'll have to write in other programming
+languages. But alas you have been fully [Haskell-brained][kmett] and lost all
+ability to program unless it is type-directed, you don't even know how to start
+writing a program without imagining its shape as a type first.
+
+[kmett]: https://x.com/kmett/status/1844812186608099463
+
+To feed your addiction you've already learned how to fake ADTs and monads in
+Java and C++, and maybe you're writing in a language that actually supports
+them already like purescript or dhall. But you're actually looking for the good
+stuff, that GADT hit. Alas, even langauges that support ADTs (or can be
+coerced into supporting them) might not support GADTs. Unless ...